/**
 * User: alesj
 * Date: 2005.6.13
 * Time: 16:06:57
 *
 * (C) Genera Lynx d.o.o.
 */

package com.generalynx.common.utils;

import java.util.Random;

public class RandomStringUtils {

    private static final Random RANDOM = new Random();

    public RandomStringUtils() {
    }

    public static String random(int count) {
        return random(count, false, false);
    }

    public static String randomAscii(int count) {
        return random(count, 32, 127, false, false);
    }

    public static String randomAlphabetic(int count) {
        return random(count, true, false);
    }

    public static String randomAlphanumeric(int count) {
        return random(count, true, true);
    }

    public static String randomNumeric(int count) {
        return random(count, false, true);
    }

    public static String random(int count, boolean letters, boolean numbers) {
        return random(count, 0, 0, letters, numbers);
    }

    public static String random(int count, int start, int end, boolean letters, boolean numbers) {
        return random(count, start, end, letters, numbers, null, RANDOM);
    }

    public static String random(int count,
                                int start,
                                int end,
                                boolean letters,
                                boolean numbers,
                                char chars[]) {
        return random(count, start, end, letters, numbers, chars, RANDOM);
    }

    public static String random(int count,
                                int start,
                                int end,
                                boolean letters,
                                boolean numbers,
                                char chars[],
                                Random random) {
        if (count == 0) {
            return "";
        }
        if (count < 0) {
            throw new IllegalArgumentException("Requested random string length " + count + " is less than 0.");
        }
        if (start == 0 && end == 0) {
            end = 123;
            start = 32;
            if (!letters && !numbers) {
                start = 0;
                end = 2147483647;
            }
        }
        StringBuffer buffer = new StringBuffer();
        int gap = end - start;
        while (count-- != 0) {
            char ch;
            if (chars == null) {
                ch = (char)(random.nextInt(gap) + start);
            } else {
                ch = chars[random.nextInt(gap) + start];
            }
            if (letters && numbers && Character.isLetterOrDigit(ch) ||
                    letters && Character.isLetter(ch) ||
                    numbers && Character.isDigit(ch) ||
                    !letters && !numbers) {
                buffer.append(ch);
            } else {
                count++;
            }
        }
        return buffer.toString();
    }

    public static String random(int count, String chars) {
        if (chars == null) {
            return random(count, 0, 0, false, false, null, RANDOM);
        } else {
            return random(count, chars.toCharArray());
        }
    }

    public static String random(int count, char chars[]) {
        if (chars == null) {
            return random(count, 0, 0, false, false, null, RANDOM);
        } else {
            return random(count, 0, chars.length, false, false, chars, RANDOM);
        }
    }

}
